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S. Pu et al. / Tetrahedron 61 (2005) 6623–6629
Scheme 2.
NMR (400 MHz, CDCl3) d 2.47 (s, 3H), 7.05 (s, 1H), 7.44–
7.51 (m, 3H, JZ6.4 Hz), 7.76–7.849 (m, 3H, JZ8.8 Hz),
8.20–8.24 (q, 1H, JZ8.0 Hz).
4.2.6. 1,2-Bis(2-methyl-5-fluorophenyl-3-thienyl)per-
fluorocyclopentene (2a). Compound 2a was synthesized
by the same procedure used for the preparation of 1a. The
crude product was purified by column chromatography on
silica gel to obtain 2a in 45% yield as baby blue solid: mp
69–71 8C: HRMS (ESI): MCHC, found 557.0630.
C27H16F8S2 requires 557.0638; MS m/z 557 (MC1), 556
(M), 541 (–CH3), 526 (–2CH3), 480 (–4F): 1H NMR
(400 MHz, CDCl3) d 2.50 (s, 6H), 6.71 (s, 2H), 7.023–7.096
(m, 4H, JZ8.4 Hz), 7.474–7.509 (m, 4H, JZ7.6 Hz). 13C
NMR (400 MHz, CDCl3) d 14.8, 115.9, 122.4, 125.9, 127.1,
4.2.2. 3-Bromo-2-methyl-5-(p-fluorophenyl)thiophene
(7). Compound 7 was prepared by a method similar to
that used for 6 and obtained as buffer solid in 71% yield: 1H
NMR (400 MHz, CDCl3) d 2.48 (s, 3H), 7.05 (s, 1H), 7.04–
7.08 (t, 2H, JZ8.8 Hz), 7.52–7.55 (q, 2H, JZ7.2 Hz).
4.2.3. 3-Bromo-2-methyl-5-(p-ethoxylphenyl)thiophene
(8). Compound 8 was prepared by a method similar to
that used for 6 and obtained as white solid in 72% yield: mp
108–110 8C: 1H NMR (400 MHz, CDCl3) d 1.42 (t, 3H, JZ
7.0 Hz), 1.98 (s, 3H), 4.09 (q, 2H, JZ7.6 Hz), 6.95 (s, 1H),
7.05–7.49 (q, 4H, JZ8.0 Hz).
129.6, 130.9, 139.51, 140.9, 160.8, 163.8. IR (KBr, cmK1
2970, 2919, 1602, 1510, 1231.
)
4.2.7. 1,2-Bis(2-methyl-5-p-ethoxylphenyl-3-thienyl)per-
fluorocyclopentene (3a). Compound 3a was synthesized by
the same procedure as that use for 1a. The crude product
was purified by column chromatography on silica gel to
obtain in 51% yield as baby blue solid: mp 101–103 8C:
HRMS (ESI): MCHC, found 609.1346. C31H26F6O2S2
requires 609.1351; MS m/z 609 (MC1), 608 (M), 593
(–CH3), 578 (–2CH3): 1H NMR (400 MHz, CDCl3) d
1.409–1.444 (t, 6H, JZ6.8 Hz), 2.38 (s, 6H), 4.011–4.078
(q, 4H, JZ7.2 Hz), 6.98 (s, 2H), 7.15 (q, 4H, JZ8.0 Hz),
7.438–7.493 (q, 4H, JZ8.8 Hz). 13C NMR (400 MHz,
CDCl3) d 14.5, 63.6, 114.9, 122.5, 122.8, 124.5, 125.9,
126.8, 129.6, 130.9, 133.2, 140.4, 142.2, 158.8. IR (KBr,
cmK1) 2981, 2927, 1609, 1515, 1338, 1254.
4.2.4. 3-Bromo-2-methyl-5-(p-(N,N-dimethylamino)
phenyl)thiophene (9). Compound 9 was prepared by a
method similar to that used for 6 and obtained as yellow
1
solid in 79% yield: H NMR (400 MHz, CDCl3) d 2.37 (s,
3H), 2.98 (s, 6H), 6.93 (s, 1H), 7.24–7.45 (q, 4H, JZ
8.4 Hz).
4.2.5. 1,2-Bis(2-methyl-5-naphthyl-3-thienyl)perfluoro-
cyclopentene (1a). To a stirred solution of 6 (3.03 g;
10.0 mmol) in THF was added dropwise, a 4.0 mL n-BuLi
solution (2.5 mol/L, 10.0 mmol) at K78 8C under nitrogen
atmosphere. Stirring was continued for 30 min at K78 8C.
Perfluorocyclopentene (0.68 mL; 5.0 mmol) was slowly
added to the reaction mixture at K78 8C, and the mixture
was stirred for 2.5 h at same temperature. The reaction was
quenched by water. The product was extracted with ether.
The organic layer was washed with 1 M aqueous HCl and
water. The organic layer was dried over MgSO4, filtrated
and evaporated. The crude product was purified by column
chromatography on silica gel using petroleum ether/acetic
ether (15:1) as the eluent and 4.15 g of 1a obtained as baby
blue oil in 67% yield: HRMS (ESI): MCHC, found
621.1145. C35H22F6S2 requires 621.1140; MS m/z 621 (MC
1), 620 (M), 605 (–CH3), 590 (–2CH3): 1H NMR (400 MHz,
CDCl3) d 2.20 (s, 6H), 6.99 (s, 2H), 7.478–7.535 (m, 6H,
JZ12.0 Hz), 7.761–7.888 (m, 6H, JZ8.0 Hz), 8.203–8.243
(m, 6H, JZ8.4 Hz). 13C NMR (400 MHz, CDCl3) d 14.5,
115.9, 122.7, 123.9, 124.9, 125.7, 126.5, 128.8, 130.9,
131.6, 133.9, 134.9, 139.2. IR (KBr, cmK1) 3059, 2924,
1592, 1509, 1440, 1275, 1195.
4.2.8. 1,2-Bis(2-methyl-5-p-(N,N-dimethylamino)phenyl-
3-thienyl)perfluorocyclopentene (4a). Compound 4a was
synthesized by the same procedure as that use for 1a. The
crude product was purified by column chromatography on
silica gel to obtain 4a as cyan solid in 55% yield: mp 140–
142 8C: HRMS (ESI): MCHC, found 607.1667.
C31H28F6N2S2 requires 607.1671; MS m/z 607 (MC1),
1
606 (M), 591 (–CH3), 576 (–2CH3): H NMR (400 MHz,
CDCl3) d 2.17 (t, 12H, JZ8.8 Hz), 2.97 (s, 6H), 6.73 (s,
2H), 7.25–7.43 (q, 8H, JZ8.4 Hz). 13C NMR (400 MHz,
CDCl3) d 14.8, 40.6, 112.6, 120.1, 125.8, 126.7, 128.4,
135.9, 142.8, 149.6. IR (KBr, cmK1) 2964, 2931, 1609,
1524, 1361, 1263.
Acknowledgements
This work was supported by the Projects of Fundamental